Anti-Lock Brake System: Description

Anti-Lock Brake System (ABS) consists of an actuator, control relay (solenoid relay and motor relay), ABS Electronic Control Unit (ECU), and 4 wheel speed sensors. ABS actuator may be of either Bosch or Nippondenso design. On models with Bosch actuator, ECU and relay are part of actuator assembly. See Figure or Figure.

An ABS indicator light is located on the instrument cluster. Indicator light comes on for 3 seconds as a bulb test when ignition is turned on. A primary check is performed after each engine start, and initial vehicle speed exceeds 4 MPH. If brake pedal is pressed before vehicle speed exceeds 4 MPH, the primary check will not occur until brake pedal is released.